In this study, BMP tests were performed with flocculated algal bio-mass under optimal doses of each coagulant. The same mixed liquor sample was used for both flocculants (160 NTU). As shown in Fig. 7, none of the studied natural flocculants showed a clear effect on the an-aerobic biodegradability of flocculated microalgal biomass in BMP tests. Accumulated methaneyieldwas163mL CH4/gVSforthecontrol(grav-ity settled microalgae) and 162 and 166 mLCH4/g VS after coagulation– flocculation with Ecotan and Tanfloc, respectively. The methane content in biogas was the same in all cases (70%). The methane yield was com-parable with that achieved in our previous studies with microalgal bio-mass grown in domestic wastewater [24,28].